1. Field
One or more embodiments herein relate to an organic light emitting device.
2. Description of the Related Art
An organic light emitting diode display generates images based on light emitted from a plurality of pixels. Each pixel includes an organic light emitting diode formed from an emission layer between two electrodes. In operation, electrons injected from one electrode and holes injected from the other electrode combine in the emission layer to generate an excitons. Light is emitted when the excitons change state. An organic light emitting diode display is therefore considered to be self-emission type of display.
The pixels of an organic light emitting diode may have various structures. In one type of pixel, a storage capacitor, a switching transistor, and a driving transistor are included to control operation of the organic light emitting diode. The driving transistor controls flow of driving current to the organic light emitting diode. The storage capacitor is connected to a driving gate node of the driving transistor and stores a voltage which is based on a data voltage for one frame. With this arrangement, during one frame, a constant amount of driving current is supplied to the organic light emitting diode from the driving transistor to induce the emission of light.
However, parasitic capacitance may occur between the driving gate node of the driving transistor and a data line and/or between the driving gate node of the driving transistor and an overlapped portion of a scan line. As a result, a voltage change in the data line or a scan signal of the scan line may affect the voltage of the driving gate node of the driving transistor. This, in turn, may change the driving current flowing to the organic light emitting diode, thereby causing vertical crosstalk that generates luminance variation that deteriorates display quality.
One approach which has been proposed in an attempt to prevent crosstalk involves forming a large gap between the data line and the driving gate node. However, this approach may be inadequate and may not be able to be performed in all cases. For example, in a high-resolution display, the size of the pixels is very small and thus may not accommodate formation of the gap. Also, process design rules may not be able to be gradually reduced due to limits in equipment specification and photolithography capacity. These effects deter efforts to minimize pixel size and also prevent any significant reduction in vertical crosstalk.